Rotary plows are usually provided with support wheels on the plow frame to provide a distance of the plow frame from the ground surface and thus the penetration depth of the plow tools into the ground. Since the plow frame is angled obliquely to the direction of travel in the working position, support wheels pivot in the direction of travel during the rotary movement of the plow frame. In their pivoting movement, these require a smaller clearance with respect to the plow frame than support wheels which pivot in the opposite direction to the direction of travel if these are not arranged at the end of the plow frame. In principle, however, the pivot arm of these support wheels is inclined backwards in the working position, since self-stabilization and self-alignment of the wheels takes place precisely with changing forces on the support wheels. This improves or makes possible a stable and exact lateral guidance of the plow tools, as shown in the German patent application DE 30 33 791. In order to move the pivot arm backwards when the support wheel is placed on the ground in forwards travel, the support wheel is provided with an extension as a ground spike or it is provided with a braking device or the like, as for example disclosed in DE 75 38 474 U1 or DE 25 54 273 C2. A further pendulum support wheel as disclosed in DE 25 45 009 C3 may be perpendicularly pivoted about an axis in order to serve as a freely-rotating transport wheel in a middle transport position of the plow frame. Since these support wheels occasionally pivot forward upon touching the ground and do not fulfill their depth control function, support wheels have been implemented which basically pivot counter to the direction of travel, but need a larger pivoting clearance relative to the plow frame, but which then lacks ground clearance when turning the lifted plow. The German utility model DE 8532966 U1 proposes a pendulum support wheel, which is arranged behind the plow frame. In order to allow for boundary plowing, the support wheel may be temporarily folded forward about a vertical axis. As previously described, however, this displaced position causes an unstable lateral guidance of the plow tools, which leaves a bad and uneven plow pattern in the final furrow. The German utility model DE 299 19 028 U1 proposes a pushed support wheel with the same disadvantages.
It is an object of the invention to provide a pivoting support wheel which avoids the above-mentioned drawbacks but combines the respective advantages.